BoilerFaultCodesYour boiler has stopped working because it cannot accurately measure the temperature of the water returning to the unit due to a faulty sensor or wiring.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return–NTC open circuit. NTC broken, NTC cable broken, Defective connection at NTC, Defective connection at electronics
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that monitors water temperature coming back from your radiators. The most common reason is that the sensor has physically failed or a wire has shaken loose, meaning the boiler can no longer safely regulate its heat output. Because the system doesn't know how hot the water is, it shuts down immediately to prevent internal overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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